Analysis of the theaflavin composition in black tea (Camellia sinensis) for predicting the quality of tea produced in Central and Southern Africa

A parameter of black tea that correlates with quality is highly desired. Twenty good and 20 poor quality tea clones were selected from the breeding programme at the Tea Research Foundation (Central Africa) (TRF(CA)). The theaflavin (TF) composition of the black tea manufactured from each clone was analysed by capillary electrophoresis and correlated with total scores and valuation from two tea tasters with regression analysis. The significance of the differences between the 20 good and 20 poor quality tea clones was determined with the Student t-test and the distribution-free Kruskal-Wallis test. The sum of the TFs of the black tea correlated well (r = 0.785, P = 0.0002) with the value of the tea. Of the individual TFs determined in the black tea, the highest correlation was obtained with TF-3′-monogallate (TF-B) (r = 0.788, P = 0.0016), TF-3-monogallate (TF-A) (r = 0.741, P = 0.0004) and free TF (TF-f) (r = 0.705, P = 0.0002). TF-B (m = 24.90) followed by TF-A (m = 12.48) showed the steepest slopes against value, making them good indicators for value. The TF-digallate (TF-dg) content did not show significant correlation with value (r = 0.316, P = 0.358). The individual TF content thus can be used for optimising the black tea manufacturing process in Central and Southern Africa. © 2002 Society of Chemical Industry.